“Snowpiercer,” a futuristic action thriller directed by of-the-moment filmmaker Bong Joon-ho, is being positioned as a smart, stylish alternative to its blunt-force cousins at the multiplex, an invidious comparison that is understandable but not entirely earned.

Adapted from a French graphic novel about global warming, a new Ice Age and an arklike train that carries survivors on an endless loop like a circumnavigating monorail, “Snowpiercer” also is an Orwellian allegory about wealth disparity and political inequality that, in post-Occupy times, occasionally lights up with torch-and-pitchfork verve. The self-contained dystopia is ruthlessly segregated by class and caste, with the poor and dispossessed huddling in its tail section while the decadent 1 percent live it up in first class. The entire clattering, Dante-like construction is helmed by the mysterious Mr. Wilford, a secular god who enforces the train’s apartheid regime with unseen, authoritarian resolve.

As “Snowpiercer” opens, one of several populist revolutions is being plotted, this time by a charismatic but reluctant leader of men named Curtis (Chris Evans) and his elderly mentor, Gilliam (John Hurt). After two small children are removed from the tail section by a cruel Wilfordian toady, the uprising gets underway, with Curtis leading his team — including a determined mother played by Octavia Spencer — through succeeding cars as if on a journey through civilization itself.

Far from the fetid netherworld of the tail section, the train’s first-class passengers enjoy a greenhouse, a library, an aquarium (and adjacent sushi bar) and a candy-hued kindergarten, where a whey-faced teacher (Alison Pill) indoctrinates their well-groomed children in the importance of their own genetically inherited social station. It’s a vision that’s part “The Hunger Games,” part Ayn Rand and part Wachowski, with some Wes Anderson thrown in for whimsical measure. When a barely recognizable Tilda Swinton shows up as Wilford’s chief factotum, she seems to be dressed in castoffs from “Moonrise Kingdom” and “The Grand Budapest Hotel,” right down to her prosthetic teeth, which, combined with a thick Scottish brogue, make her sound like a vaguely fascistic Miss Brodie.

Swinton’s turn is among the most colorful and amusing in “Snowpiercer,” but it’s virtually lost in a tonal mishmash that can never decide between thoughtful political metaphor, lightheartedness and pulverizing violence. Bong seems most at home with the latter, which he stages with tiresome, slow-motion fetishism, mixing costumes and weaponry in an effort to distract from the scenes’ sheer repetitiveness.

He also indulges in eye-rolling contrivances, including some convenient and-then-they-woke-ups and a pivotal kid with, apparently, a keen eye for finding just the right fur coat to wear when all hell is breaking loose. Such cheats notwithstanding, “Snowpiercer” is full of dazzling visuals, as Bong leads viewers through the train’s well-appointed strata and as its denizens take in the frozen world outside its windows.

What’s more, the film’s global consciousness is accentuated by a cast that includes South Korean actors Song Kang-ho and Ko Asung, as a father and daughter hooked on a drug called Kronol, which, in another conspicuous convenience, Bong makes sure we know is not just addictive but highly flammable. Subtlety may not be the film’s strong suit, but it creates a richly imagined world, as glitteringly arresting as it is savagely merciless.